The security of aircrafts and their occupants have become an increasing concern for civil aviation in the past two decades. Specifically, civil aircrafts have become prime targets for terrorists and saboteurs. Further, as a result of the dramatic increase in drug trafficking there have been increased attempts to smuggle illegal drugs and other contraband aboard business aircrafts.
While various electromagnetic intrusion sensor systems have been previously available, such systems have had certain attendant disadvantages. Specifically, the prior systems have been complex in design and costly to produce and install requiring exact calibration and alignment procedures, involving highly trained professionals. As a result, the systems have not been routinely included in corporate aircrafts. Further, false alarms have frequently occurred due to e.g., power fluctuations, environmental changes, or sensor malfunctions. Further, the utilization of multiple sensors in close proximity to each other has been difficult due to mutual interaction of the sensing fields. Finally, the prior systems have required substantial amounts of power in operation, thereby making battery operation difficult.